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C
CMuse3-Newcomer
3-Newcomer
July 30, 2026
Question

Bad quality tags using OPC UA Client Driver

  • July 30, 2026
  • 2 replies
  • 80 views

I have a OPC UA server (on a siemens comfort panel) that I want to read in some tags on my Kepware Server 7.1.271.0 server. I’ve set up an OPC UA channel and device, and I’m able to perform automatic tag generation tasks (I’m able to see the tags I have configured over there). The problem is that when I then try to read Kepware’s tags from this, the tag quality is bad. Maybe about once a minute I get a message in the log that the OPC UA Client driver is reconnecting due to connection loss- which sometimes, but not always corresponds to one momentary instance when the tag quality goes good and I’m able to read in the tags.

 

The authentication is not using any security policy or message mode.

 

I’m a bit flummoxed because I’m able to set up an Unified Automation OPC UA client that can read from the client just fine on the same machine as the Kepware server with the same settings. I did some debugging with Wireshark and saw that OPC traffic from that client to the panel was normal, while the traffic coming from Kepware to the panel would have its TCP connection establish procedure get cut off by RST packet from the panel. So I think the panel is unhappy about something from Kepware but not the UA client.

 

I did check the certs on the panel and nothing in the rejected folder.

 

Any help would be appreciated! 

2 replies

C
CMuse3-NewcomerAuthor
3-Newcomer
July 31, 2026

I managed to identify my issue, apparently I had only the x64 versions of .NET and ASP.NET 8- it was breaking the OPC UA gateway service (though I’m honestly surprised I got any data at all)

Edit: Didn’t actually fix the problem, I realized I had selected the wrong server when testing. Issue persists

M
MRohillaCommunity Manager
Support
August 6, 2026

Greetings ​@CMuse,


Since the UA client connects successfully while Kepware experiences periodic disconnects, the issue is likely related to the Siemens Comfort Panel OPC UA server resource limits and Kepware communication settings.

We recommend the following:

  • Reduce the Max Items per Read/Write/Subscribe in Kepware to 50-100 items.
  • Increase Request Timeout and Connect Timeout to 10 seconds (10000 ms).
  • Set the OPC UA Publishing Interval to 1000 ms or higher and ensure the sampling interval is not faster than the publishing interval.
  • Verify that no other OPC UA clients are connected, as Comfort Panels support only a limited number of concurrent sessions.
  • Check the configured Keep-Alive settings and set them to around 5000 ms.
  • Confirm that the OPC UA endpoint URL, security mode, and authentication settings in Kepware match the panel configuration.

Based on our experience, reducing the subscription/request size and increasing the publishing interval resolves most OPC UA connection reset issues with Siemens Comfort Panels.

Please let us know if the connection becomes stable after making these changes.

Regards,

Mohit

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